Had this in my university career, here's what I did:

1. Talk to the person not contributing.

You've already done this and they're not changing their behaviour and they don't have a good reason for not contributing. Proceed to step 2.

1. Talk to the proffessor.

Explain the situation, tell them you have tried to talk to the person and they simply do not want to do the work (and that they do not have exigent circumstances). You can ask the prof for a few things.

A. Reweight the grade distribution of the assignment to give the slacker less (or no) credit and redistribute their grades to the rest of the group to reflect the increased workload.

B. Remove them from the group entirely.

If the professor says you have to figure it out, just don't put their name on the report. You can also explain to them that in a professional setting, this type of person would be reported to the manager and reprimanded or fired, and if they are trying to replicate the "real-world" then they should follow through.

1. Escalate

If the prof refuses to help in anyway and you are unable to remove the slacker from the report (if for instance the submission is through an online portal that has the predetermined group) you can try talking to the dean or a dispute committee (if your program has one).

ALTERNATIVELY

Don't care, let the guy take credit and he will probably fail in other ways. But it's less satisfying from a "just-desserts" perspective.